I got lucky when I entered Kvatch at level 10. As an archer. Yeah, it damn well was a challenge, but the sigil stone I managed to enchant my bow with gave 10 electric damage and I pretty much won the quest because of it. Well, my arrows were goen halfways through, because I counted on finding some on the way and didn't stockpile any.
The best part of Kvatch was when I stormed the castle with Suuvlan Matius, the captain. He would be blown unconscious after maybe three hits and I'd have to manage with a broken daedric longsword with my meager blade skill of 44 against a horde of daedra. :D Even though I kept yelling obscenities to the monsters everytime I missed my power attack or was staggered by a block("****! How's this even possible!" YOU SODDIN' ****MUNCHERS!"), it was actually rather enjoyable. I admit I did consider starting a new character when entering the church undercroft killed off all but one of the imperial legionnaires and the guard with the key(Ibean?) was killed right after, when entering the main yard revealed a dozen fire atronachs with a few clannfears and scamps to boot.
The worst thing in Kvatch was the horrible lighting and the governing grey tone. I had to turn brightness to max in order to manage some hits against my foes. Scaling also wanted to have buttsechs with my poor Jacques. There was a daedroth, 8 feet of grey crocodilish ninja turtle power, in the counts quarters. I tried, died and loaded and earlier save. Never saw that daedroth again, there was just another fire bitch after the load.